Application of foam to suppress rock dust in a large cross-section rock roadway driven with roadheader

The greatest source of rock dust on rock roadway heading face is the roadheader. Overexposure to respirable rock dust can be a serious health hazard to roadheader operators and other workers. One of the rock roadways, named North Belt Main Entry (NBME), belonging to the underground coal mine Zhuxianzhuang, located in east China, is being driven by the EBZ318H roadheader. The cross-section of the roadway is 15.84 m2, and the heading face has a high concentration of respirable rock dust. This paper presents a study of rock roadheader dust control by foam, taking into account the dust generation characteristics. A new foam preparation system and application method has been proposed and the dust suppression effect of foam has been assessed by dust concentration measurements taken at two points next to the roadheader operator in the previously mentioned underground coal mine. The results have shown that the foam dramatically reduced the rock dust concentrations. The roadheader operator’s respirable dust exposures were lowed from 540.2 mg/m3 to 84.3 mg/m3, and the dust suppression efficiency reached 84.4% on the NBME heading face. In addition, the visibility and environment of the heading face was significantly improved. It is concluded that the foam showed a significant improvement on the rock dust capture efficiency, and avoided the main deficiencies of conventional water sprays.